Browse Prior Art Database

Look-Ahead Buffer Extended Operation

IP.com Disclosure Number: IPCOM000111373D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Inoue, K: AUTHOR [+3]

Abstract

Disclosed is a procedure for Look-Ahead Buffer (LAB) operation handling for a Hard Disk Drive (HDD). If a Hard Disk Controller (HDC) has no capability to receive a message when it is under operation, a microprocess or has to abort the previous operation or wait the completion of the previous operation. It requires more than one-revolution time for HDC to start the next LAB operation. It can not continue the LAB operation effectively. But this procedure does not require extra time to start the next LAB operation. It can continue the LAB operation continuously with zero latency. This improves the performance of disk read operation.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 58% of the total text.

Look-Ahead Buffer Extended Operation

      Disclosed is a procedure for Look-Ahead Buffer (LAB) operation
handling for a Hard Disk Drive (HDD).  If a Hard Disk Controller
(HDC) has no capability to receive a message when it is under
operation, a microprocess or has to abort the previous operation or
wait the completion of the previous operation.  It requires more than
one-revolution time for HDC to start the next LAB operation.  It can
not continue the LAB operation effectively.  But this procedure does
not require extra time to start the next LAB operation.  It can
continue the LAB operation continuously with zero latency.  This
improves the performance of disk read operation.

      A distinctive feature of this procedure is to modify the ending
points of LAB operation without aborting the current LAB operation.
To achieve this, the HDC includes a communication register to
communicate with the microprocessor.  By using the communication
register, the microprocessor can send a message to modify the ending
points of the LAB operation when the HDC is under operation.

The following procedure enables to execute an LAB extended operation
effectively.

      (1) Set command.
            A host system sends a read command to the HDD during LAB
            operation.

      (2) Send LAB extend message.
            HDD control program checks the requested area.  If a part
of
            requested area is in the cur...